Description: Main axis with transverse and longitudinal divisions ending with a large apical cell. To 3 cms long and tufted with few irregular branches.

Habitat: Not un-common. Littoral and upper sublittoral to 6 m, epilithic on sand covered rock.

Distribution: Widely distributed around the British Isles. Europe: France, Netherlands, Baltic Sea, Sweden, Norway, Spitzbergen and Iceland. Greenland. Atlantic coast of North America: Canada, Maine, New Hampshire, Connecticut and Long Island.

Similar Species: Most species of Sphacelaria, and other small branched brown algae, are very alike and require microscopic examination for identification.

Distribution Map from NBN: Sphacelaria radicans at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Sphacelaria radicans at iNaturalist World Species Observations database.

GBIF data for Protohalopteris radicans

WoRMS: Sphacelaria radicans at World Register of Marine Species. Accepted name: Protohalopteris radicans (Dillwyn) Draisma, Prud'homme & H.Kawai, 2010. AphiaID: 624202.

Classification: Biota; Chromista; Harosa; Heterokonta; Ochrophyta; Phaeophyceae; Dictyotophycidae; Sphacelariales; Sphacelariaceae; Sphacelaria